The present invention relates to improvements in pipe couplings or fittings, and more particularly to improvements in flexible pipe couplings.
A flexible pipe coupling comprises a flexible tubular member (hereinafter called hose for short) and means for securing the ends of the hose to the respective ends (e.g., flanges) of two metallic, plastic or like pipes. It is already known to utilize in a flexible pipe coupling a hose which has an outwardly bulging median section and two outer sections. The hose consists of rubber or elastomeric synthetic plastic material. The means for connecting the outer sections to pipes comprises rings through which the outer sections extend, which have grooves for portions of the outer sections, and which can be fastened to the respective pipes. The median section of the hose compensates for eventual variations in the distance between the pipes as well as for eventual lateral displacements of the pipes relative to each other. The outer sections must sealingly engage the connecting rings as well as the pipes.
Flexible pipe couplings of the just outlined character exhibit many important advantages. However, they are not sufficiently reliable when the pressure of fluid in the pipes is relatively high or very high. Moreover, such conventional flexible pipe couplings cannot stand excessive temperatures and/or pronounced fluctuations of temperatures, either within or outside of the pipe line in which the coupling is mounted. It has been found that, when the pressure in the interior of the flexible coupling rises, the end sections of the hose are likely to become disengaged from the connecting rings and/or from the flanges of the respective pipes so that the pressurized fluid escapes into the surrounding atmosphere.